This article researches the wave dynamic effect on back silting in the deep-water channel at north passage in the mouth bars of the Yangtze estuary.The results indicate that:1)There is a close relation between the fluid mud in the deep-water channel at north passage and the wave in the mouth bars.The amount of fluid mud has positive correlation with the wave energy,the more wave energy,the larger amount of fluid mud;the longer the wave period,the longer the duration time.2)Large amount of fine sediment will be dialyzed from the riverbed under the strong waves,which are the main part of fluid mud in the channel.3)The variation of back silting in the deep-water channel shows a good agreement with the wave evolution in macroscopic and microscopic scale.4)After the strong waves caused by typhoon,effects on the bed don’t end right the moment and will last a period of time.